1. Field of the Invention
The present invention relates generally to the field of pontoon watercraft, and flotation techniques for such watercraft. More particularly, the invention relates to an integral pontoon for a watercraft, and a technique for manufacturing the integral pontoon using molding techniques for forming a skin-foam structure.
2. Description of the Related Art
A variety of techniques may be used for floating pontoon watercraft. Traditionally, a deck structure was mounted on a flotation made of wood. For example, a floatable platform could be formed by bounding together a number of logs, or a watercraft hull could be formed by applying slats of wood over a structural frame. However, these structures were typically very bulky, tended to leak and rot, required significant maintenance, and had limited contours and configurations. Fortunately, modern manufacturing techniques and a variety of materials have largely replaced the traditional wood structure.
Some flotation devices, and watercraft components, have been manufactured from metals such as aluminum. For example, aluminum hulls are common for small fishing boats. Similarly, pontoon boats generally have metallic pontoons, or elongated flotation members, which are formed as hollow cylinders having aluminum or other metallic shells. Relative to the traditional wood structures, metal provides greater strength, eliminates problems with rot and porosity of the wood, allows greater control over boat contours, and allows the creation of pontoons having a hollow core. While these metal structures have advantages over the traditional wood structures, the metallic pontoons are generally very bulky, difficult to transport, expensive to make and repair, corrosive, and are difficult to form in aerodynamic contours for performance in the water. Furthermore, metal pontoons generally have at least two sections bonded together to form a closed structure, and potentially leak through seams or punctures in the metal shell.
Currently, most of the marine industry utilizes fiberglass in boat hull designs particularly for recreational boats. To form a fiberglass boat hull, an outer shell is formed, typically over an open die, by laying or spraying fiberglass strands or fabric on the die along with a polymeric resin. The fabric and fiber content of specific regions may be carefully controlled to provide the necessary structural integrity and for supporting fittings, reinforcing components, and the like. Once the resin is cured, the resulting structure is removed from the die and finished by trimming the fiberglass and resin, and by assembling the component with other components and subassemblies of the final product.
While traditional fiberglass construction techniques provide good structural strength and water tight properties, there are drawbacks. For example, conventional fiberglass fabrication techniques are relatively time consuming and labor intensive. Moreover, products used in forming the fiberglass composite structure require special handling and disposal, adding further to the cost of manufacturing. Depending upon the size of the watercraft and its outer configuration, fiberglass structures may require stringers, reinforcing plates, and other structural elements to provide the necessary stiffness and resistance to flexure and impact. In addition, while the fiberglass provides a watertight shell, the shell is somewhat susceptible to puncture or fracture in a situation where the watercraft becomes grounded or strikes a submerged object. Because the fiberglass itself provides no additional buoyancy, lightweight components are commonly added to the watercraft, such as between the hull and interior walls or deck sections, further adding to the cost of the final product.
Despite the widespread use of fiberglass for boat hulls, pontoon boats generally continue to use metals, such as aluminum, to form the pontoons. While fiberglass is particularly well suited for boat hull designs, pontoons are closed structures. Fiberglass is generally applied to an open die to form a smooth outer surface having features of the die. Accordingly, an alternative technique to conventional fiberglass construction is needed for pontoons.
Other techniques have been proposed, but there are unfortunate drawbacks for pontoon construction. For example, it has been proposed to manufacture small watercraft such as canoes of moldable plastic materials. In one known technique, a boat hull is rotationally molded of layers of crosslinked and non-crosslinked polyethylene in an open mold. The technique produces a composite structure made up of outer and inner layers of dissimilar materials. However, this technique seriously limits the ability to recycle any of the material. Moreover, the use of an open mold presents difficulties in maintaining any control over local or overall thickness in the resulting product, and introduces potential for warping and drawing of the product during cooling cycles.
Accordingly, it would be desirable to provide an improved pontoon for watercraft, and a technique for fabricating the pontoon, which is both economical and avoids the drawbacks of such existing approaches. For example, it would be desirable to provide an integral flotation device (e.g., pontoon) having a skin-foam structure and features integrated into the skin of the flotation device. It would also be desirable to provide a pontoon having a uniform skin, which is non-corrosive, easily repairable, and has aerodynamic contours.
The present technique features a molded component for a watercraft, wherein the component has a shell and an inner foam layer. The molded component may have a plurality of surface features and structures integrally formed in the shell, which may have desired structural characteristics and properties depending on the material and controllable parameters of a molding process. For example, the skin may be composed of a plastic or other moldable materials and structural additives. The inner foam layer is distributed about an inner surface of the shell and may have desired properties depending on the material and technique for foaming the material. Accordingly, the technique is particularly well suited for flotation devices, such as pontoons, for the watercraft.
For example, the present technique may involve a flotation system for a watercraft. In an exemplary embodiment, the system may feature an enclosure having integral structural features formed by a skin. The enclosure also may have an interior foam coupled to the skin. Depending on the particular application, the integral structural features may form a mounting structure, which may be configured for coupling to the watercraft.
The present technique also provides a novel structure for a watercraft. In an exemplary embodiment, the watercraft may feature a watercraft structure and a closed shell configured for floating the watercraft structure. A skin may define the closed shell, which may have a foam coupled to the interior of the skin. The skin also may define an integral mounting structure configured for supporting a portion of the watercraft structure.
The present technique may also involve a method of forming a watercraft. In an exemplary embodiment, the method may feature rotating and heating a closed mold having a charge of material introduced therein, and spreading the material about an inner mold surface of the closed mold. The method also may feature distributing and foaming a second material, introduced into the closed mold, about a surface of the material. Also, the method may involve removing an integral flotation structure from the closed mold, and coupling it to a watercraft structure. Advantageously, the integral flotation structure may have a skin of the material and a foam of the second material coupled to the skin.